The present invention relates to a device for ascertaining the dimensions of an object in a general sense, and particularly a human being; and more particularly the invention relates to acquiring topological measurements of a person by projecting a pattern of horizontal raster lines onto the body of that object (person), at a 45.degree. projection angle and under utilization of a mirror; an image is produced of the surface of that object upon which is superimposed that projected line pattern.
Devices of the kind to which the invention pertains are known for example from German patent application A1 38 31 630; see also U.S. Pat. No. 4,987,432 issued Jan. 22, 1991. This known device includes a projector for the projection of a raster line pattern, the projector being arranged behind a stand on which the person stands. The mirror is inclined at an angle of about 67.5.degree. relative to the ceiling of the room in which the device or apparatus is used. More particularly, the mirror is fastened to that ceiling and hangs more or less down from there, at a location between the camera and the stand.
While generally satisfactory it was found that this arrangement has a number of drawbacks. The projector for the line raster and the camera for acquiring the topographic, image information, basically face each other, and since the projection may use a flash the imaging process may be interfered with on that account.
More of a problem however is the mirror itself which, simply speaking, is often in the way. Consider the fact that the line pattern must extend for at least 1,200 mm while the mirror will extend down from the ceiling by about a meter. Assuming that normally rooms have a height of 2.5 to 2.8 meters, that (physical) projection or extension of the mirror in a downward direction can be a considerable hindrance. It can easily be seen that in a situation involving haste or something similar, the mirror could easily be hit and damaged or at least misadjusted. Also it was found that the fastening of the mirror is surprisingly complicated.
Further to the state of the art see U.S. Pat. Nos. 4,786,925; 4,639,107 and 4,370,039.